Conventionally, an acoustic generator using a piezoelectric element has been known (see, for example, Patent Literature 1). The acoustic generator vibrates a vibration plate by applying voltage to a piezoelectric element attached to the vibration plate and by vibrating the piezoelectric element. The acoustic generator outputs sound by actively using resonance of the vibration.
Also, in the acoustic generator, a thin film such as a resin film can be used as the vibration plate. Thus, the acoustic generator can be made thinner and lighter than a general electromagnetic speaker or the like.
Note that when a thin film is used as the vibration plate, in order to obtain good acoustic conversion efficiency, it is desired that the thin film is supported in such a manner that tension is uniformly applied thereto, for example, by being held between a pair of frame members in thickness direction.